The present invention relates to an agricultural separating device and an agricultural separator including such a device.
It is well-known in the agricultural field to use starwheels when separating materials, eg clod and/or stones from root vegetables or bulbs, eg during harvesting, in de-stoning machines and also in static cleaning or grading equipment. Starwheels have a plurality of resiliently deformable "fingers" arranged around a central hub or boss and are at present formed from polyurethane or rubber, but could be formed from any other suitable material. In use, a plurality of starwheels are mounted on a rotatable shaft, commonly known as a "starshaft".
During use, damp soil may stick to the starwheels, or hard material, eg stones, may become jammed between the starwheels. This will reduce separation and produce wear of the starwheels.
GB 2 145 612 discloses two parallel starshafts arranged upstream of a counter rotating clod roller for use in separating clod and/or stones from root vegetables or bulbs. In practice, the fingers of the starwheels of adjacent starshafts are staggered and fit into the gaps between the starwheels of the adjacent starshaft. In such a position, the starshafts are said to be "interleaved". When separating potatoes, potato haulm can become wrapped around the starshafts, and interleaving the starshafts provides a degree of self-cleaning.
It is also known from EP 0 410 808 to arrange starshafts in a lifting conveyor. Although the starwheels may be interleaved, it is particularly advantageous in a de-stoning machine for there to be a radial gap between the ends of the fingers of the starwheels of adjacent starshafts, ie the starwheels of adjacent starshafts are not interleaved. There is, therefore, no self-cleaning of the starshafts.